c. A nucleotide analogue, Ribivirin, is used to treat infection in severely ill hospitalized patients

d. The virus is the leading cause for pneumonia in adults

Which of the following viruses does not contain an envelope?

a. The virus that is the major cause for acute respiratory diseases in military recruits

b. The virus that is responsible for most of the viral pneumonia in infants

c. The virus that transcribes and replicates in the nucleus

d. The virus that caused severe respiratory syndrome in 2003-4, but is no longer detected in humans now

Between 1919 and 1956, human Influenza was caused by viruses of H2N2 subtype, and there was a new pandemic. Which of the following processes was most likely responsible for the appearance of H2N2 virus?

a. Point mutations from error-prone viral RNA polymerase to generate a new subtype

b. Acquisition of the RNA segment that encodes a new subtype of NRA polymerase